The former South African president Nelson Mandela today said he was "honoured" after his statue was unveiled opposite the Houses of Parliament in London.

The prime minister, Gordon Brown, the London mayor, Ken Livingstone, and the film director Richard Attenborough were among those who paid tribute to 89-year-old Mr Mandela at the unveiling ceremony in Parliament Square.

"Nelson Mandela is one of the most courageous and best-loved men of all time," Mr Brown said. "You will be here with us always."

Speaking to crowds who gathered for the unveiling, Mr Mandela said: "It's an honour for us to be with you on the occasion of the unveiling of this statue today. We never dreamed we would all be here today.

"Though this statue is of one man, it should in actual fact symbolise all those who have resisted oppression, especially in my country."

Mr Brown compared the achievements of Mr Mandela to those of the former US president Abraham Lincoln and Sir Winston Churchill, whose statues already stand in the square.

He likened Mr Mandela's struggle against apartheid and poverty to Lincoln's efforts to tackle slavery and Churchill's battle against fascism.

The prime minister said the statue would provide a "beacon of hope that signals to anyone suffering injustice anywhere that their suffering will not last for ever, will never be in vain, and will be overcome".

Mr Livingstone said the location in Parliament Square demonstrated "that the struggle of the South African people to overcome the tyranny of the racist apartheid state was itself the struggle for universal human rights".

The mayor added: "Nelson Mandela's struggle came to symbolise the very idea of a better world, a world in which the most fundamental rights are available to each and every human being, and this is why his statue is such an appropriate addition to one of our most important squares."

Mr Livingstone had campaigned for the Mandela sculpture to be placed in Trafalgar Square - the site of Nelson's column. A constant vigil for Mr Mandela's release from prison was held in the square during the years of apartheid rule in South Africa.

However, Westminster council's planning committee decided the statue should go in Parliament Square.

An expert committee also criticised the statue as "run-of-the-mill mediocre modelling" rather than good art.